Various types of measuring apparatuses for measuring compositions, structure, chemical characteristics, etc. of a surface of a specimen or a thin film formed on a specimen have been developed.
In particular, in case of highly-integrated semiconductor, there is a need to reduce a thickness of a silicon oxide layer to 1 nm or less in 100 nm technology generation, depending on International Technology Roadmap for Semiconductors (ITRS). Further, as integration is gradually increased, the thickness of the oxide layer is to be thinner. As a result, there is a need for a new technology for analyzing an ultra-thin oxide layer. In addition, since a doped layer is thinner and thinner, it is difficult to analyze the film by a traditional surface analyzing technique such as a secondary ion mass spectroscopy (SIMS) because of surface damage and low depth resolution. Generally, the existing surface analysis apparatuses tool do not have enough resolution for an ultra-thin film or has limited performance confirming only a portion of a structure or a composition of the ultra-thin film. Therefore, a need exists for an atomic resolution analysis technology.
A MEIS is developed to meet the requirements by using a medium energy ion beam. For example, an ion beam having medium energy of several tens to hundreds of keV has about 0.3 nm energy resolution in a depth direction from a surface. As a result, the spectrophotometer using medium energy ion using 50-500 keV ion beam is more excellent than other analysis apparatuses.
The MEIS can precisely measure the energy loss of scattered 50-400 keV proton, helium, and neon from a surface or near surface atom. MEIS of 50-400 keV has 10−3 energy resolution which leads the atomic depth resolution to measure the depth profile of elementary composition of a thin film. In addition, it can obtain information on an atomic structure by using a channeling/blocking effect of ion beam, such that it is very useful for analyzing the composition and structure for the surface and interface of the ultra-thin film. Further, the MEIS can accurately calculated collision cross section of ion it quantitatively and non-destructively analyze the composition and structure of the surface and interface of the ultra-thin film.
Due to these advantages, the MEIS is substantially the only analysis technology capable of quantitatively analyzing the composition and the depth distribution of the atomic structure (crystallinity, stress, etc) of the ultra-thin film of several nm with the resolution of the atomic layer.
However, the existing MEIS apparatus has a very large size and cannot measure or map a micro area by using the non-focused ion beam having a diameter of 1 mm. In addition, the conventional MEIS consists of expensive scanner for measuring scattering angle and energy distribution and has a long measurement time.